The new iPad is a huge hit for Apple, to the tune of 3 million devices sold in the first weekend alone. And it’s no wonder — the device is a big upgrade from previous models, quadrupling the resolution of the tablet’s screen to an ultra-sharp “retina” display. However, the new model has brought with it a spate of minor issues, one of which is slowly rising to the status of “scandal.”
First there was the trouble with older smart covers not working properly on the new iPad. Then came news that the iPad gets much hotter than previous models, possibly uncomfortably so. Both issues were more or less dismissed as minor inconveniences, with the heat problem questionable from the get-go.
However, there’s yet another complication: the iPad’s battery meter is inaccurate. After a display expert discovered the iPad continues to charge the battery even after the screen says it’s at 100%. Further testing showed that the misleading indicator could cost users as much as 1.2 hours of run time.
This problem is different from its predecessors because it’s so clear-cut. Whereas another Apple gadget fracas — the iPhone 4 “antennagate” affair — was difficult to quantify in terms of actual lost calls, in this case the cost is right there in black and white: Your iPad gets an hour less run time if you unplug as soon as the meter hits full. Apple so far hasn’t made any statement on the matter, but it should, because there may be a very good reason the battery meter on the iPad is a fibber.
The lithium-ion batteries that are used in almost every piece of electronics today have a limited lifespan. Even if you don’t ever use it, if you put a battery on a shelf somewhere and try to charge it up a few years later, it won’t work. The battery will be permanently dead.
Most of us experience this with our cellphones. If you own a phone for more than a year (and most people do), you’ve probably noticed that its battery doesn’t quite have the same all-day oomph that it used to. A number of factors can accelerate battery degradation, one of them being how often it’s kept fully charged. The table below from Battery University shows how much faster fully charged batteries degrade at various temperatures.
“It’s actually better not to charge the battery fully,” says Isidor Buchmann, CEO of Cadex Electronics, a manufacturer of battery testing equipment. “If you never fully charged your iPad, the run time would be a little bit less, but you’ll keep the battery longer.”
As the table also shows, another big factor that can cut down the lifetime of a battery is heat. If you keep a gadget fully charged in a hot environment, its battery will most likely live fast and die hard. Now, some studies have demonstrated that the new iPad runs noticeably hotter than the previous model, even if it’s not uncomfortably warm.
“The worst combination is fully charged at elevated temperature,” says Buchmann. “It’s almost like food. It spoils more quickly at elevated temperature. A full charge promotes more corrosion.”
After discovering the extra heat and knowing how charge can affect battery lifespan, it’s possible that Apple purposefully designed its battery meter to tell a little white lie about its charge in the interest of extending the lifetime of the tablet. After all, it still technically gives 10 hours of use at 90%, and it’s the rare user that really needs that full 10-hour lifetime outside of a long flight.
However, Buchmann doesn’t think Apple told the iPad battery to lie. He believes Apple just did its best in creating the iPad’s battery meter, but simply got the measurement wrong since the techniques involved are notoriously inaccurate.
“How do you measure a battery’s state of charge?” he asks. “Anyone knowledgeable about batteries knows there is no way. It’s just a very rough estimate. If Apple could do it better, they would.”
I’m not sure if I share Buchmann’s theory, however. After all, if an independent researcher can figure out if the iPad is still charging past 100% with relatively simple tests, certainly the most valuable company in the world could do the same.
Still, whether is was by design or just a random quirk, the truth-challenged battery indicator on the new iPad could end up being a blessing for users who hope to keep using their tablets until 2015 and beyond. If it is random, though, then expect an update soon — a battery that inadvertently encourages responsible use would deal a blow to something Apple and every other electronics manufacturer continually relies on: planned obsolescence.
What’s your take on the iPad battery controversy?
Posted by Janine E. Mooney, Editor
March 27, 2012